<template>
  <div class="pagination">
    <button @click="$emit('newPage',pageNo-1)" :disabled="pageNo===1">上一页</button>
    <button v-show="startEndPage.start > 1" @click="$emit('newPage',1)" :class="{geactive:pageNo===1}">1</button>

    <button v-show="startEndPage.start > 2">···</button>

    <button v-for="(page,index) in startEndArr" :key="index" @click="$emit('newPage',page)" :class="{active:pageNo===page}"> {{page}}</button>

    <button v-show="startEndPage.end < totalPages - 1">···</button>
    <button v-show="startEndPage.end < totalPages" @click="$emit('newPage',totalPages)" :class="{active:pageNo===totalPages}">{{totalPages}}</button>
    <button @click="$emit('newPage',pageNo+1)" :disabled="pageNo===totalPages">下一页</button>

    <button style="margin-left: 30px">共 {{total}} 条</button>
  </div>
</template>

<script>
export default {
  name: "Pagenation",
  props:['pageNo','continuePage','total','totalPages'],
  computed:{
    startEndArr(){
        const arr = []
        for(var i=1;i<=this.startEndPage.end;i++){
            if(i>=this.startEndPage.start){
                arr.push(i)
            }
        }
        return arr
    },
    startEndPage(){
        let start = 0
        let end = 0
        const {continuePage,pageNo,totalPages} = this
        //如果连续页大于总页数
        if(continuePage>totalPages){
            start = 1
            end = totalPages
        }else{ //连续页小于总页数
            start = pageNo - Math.floor(continuePage / 2);
            end = pageNo + Math.floor(continuePage / 2);
            if(start < 1){
                start = 1
                end = continuePage
            }
            if(end > totalPages){
                start = totalPages - continuePage + 1
                end = totalPages
            }
        }
        return {start,end}
    }
  }
};
</script>

<style lang="less" scoped>
.pagination {
  button {
    margin: 0 5px;
    background-color: #f4f4f5;
    color: #606266;
    outline: none;
    border-radius: 2px;
    padding: 0 4px;
    vertical-align: top;
    display: inline-block;
    font-size: 13px;
    min-width: 35.5px;
    height: 28px;
    line-height: 28px;
    cursor: pointer;
    box-sizing: border-box;
    text-align: center;
    border: 0;

    &[disabled] {
      color: #c0c4cc;
      cursor: not-allowed;
    }

    &.active {
      cursor: not-allowed;
      background-color: #409eff;
      color: #fff;
    }
  }
}
</style>